
html,body{
   height:100%;
}
body{
    margin:0;
    padding:0;
    background-image:linear-gradient(180deg,#bcdeff,#fff,#bcdeff);
    background-attachment:fixed;
}
header{
    height:60px;
    line-height:60px;
    padding-left:30px;
    background-image:url("header.jpg");
    background-repeat: no-repeat;
    background-size:cover;
    position:fixed;
    width:100%;
    top:0;
    z-index:1;
    font-family:"Microsoft YaHei",微软雅黑,"MicrosoftJhengHei",华文细黑,STHeiti,MingLiu;
    color:#fff;
    
}
.title{
    font-size:32px;
    text-shadow:5px 5px 5px #111;
    float:left;
}
.opt{
    float:right;
    padding-right:30px;
    text-shadow:1px 1px 1px #aaa;
}
.opt a{
    text-decoration:none;
    margin-left:10px;
    color:#fff;
}
.opt a:hover{
    color:#ff0000;
}
nav {
    position:fixed;
    top:60px;
    width:100%;
    z-index:1;
    clear: both;
    /*background-color:#115eaa;*/
    /*background-image:radial-gradient(ellipse at center,#7788ff,#115eaa);*/
    background-image:linear-gradient(180deg,#115eaa,#7788ff);
    padding-left:200px;
}
nav ul{
    margin:0;
    padding:0;
    list-style-type:none;
}
nav ul li{
    display: inline-block;
}
nav ul li a{
    display:inline-block;
    width:100px;
    height:40px;
    line-height:40px;
    text-align:center;
    text-decoration:none;
    font-size:18px;
    font-family:"Microsoft YaHei",微软雅黑,"MicrosoftJhengHei",华文细黑,STHeiti,MingLiu;
    font-weight: bold;
    text-shadow: 1px 1px 5px #111;
    color:#fff;
    border-right:1px solid #fff;
}

nav ul li a:hover{
    background-color:#aaff88;
}
.active{
    background-color:#aaff88;
}

footer{
    clear: both;
    width:100%;
    height:30px;
    line-height:30px;
    color:#fff;
    text-align: center;
    background-color:rgb(138, 130, 243);
    position:fixed;
    bottom:0;
    z-index:0;
}

#content{
    position: relative;
    top:100px;
    clear: both;
    margin:10px;
    min-height:80%;
    
}
#content fieldset{
    overflow:auto;
}
#clazz{
    display:inline-block;
    width:300px;
    height:300px;
}
#course{
    display:inline-block;
    width:300px;
    height:300px;
}
#proud{
    display:inline-block;
    width:300px;
    height:300px;
}
#activity{
    display:inline-block;
    width:300px;
    height:300px;
}
#link{
    display:inline-block;
    width:300px;
    height:300px;
}